1. Technical Field
The present invention relates to a curable cyclic phosphazene compound and a method of preparing the same, and, more particularly, to a curable cyclic phosphazene compound having a low dielectric constant, a low dielectric loss index and high thermal stability, and a method of preparing the same.
2. Description of the Related Art
Recently, printed circuit boards (PCBs) and semiconductor devices have been problematic in that signal loss and signal delay phenomena are caused by the miniaturization and high-integration of devices and the increase in frequency of used signals. In order to solve this problem, conventionally, electric resistance has been decreased by changing a wiring material from an aluminum conductor to a copper conductor, and it has been required to develop low dielectric materials.
In particular, a phenol resin, an epoxy resin and the like have been used to make a conventional insulator, but they cannot be used for PCBs and the like because of the above-mentioned problem. Therefore, it is predicted that a material having a low dielectric constant and a low dielectric loss, which is developed in the present invention, be used as an insulator.
With the miniaturization, high-integration and high-densification of semiconductor devices and printed circuit boards (PCBs), insulating materials having a low dielectric constant of 3.0 or less are increasingly required because they can reduce signal delay time.
Fluorine resins have been actively developed because they have excellent resistance to heat and chemicals as well as a low dielectric constant.
For example, Japanese Unexamined Patent Application Publication Nos. 1985-104129 and 1991-282874 disclose a fluorine-containing polyimide resin (dielectric constant: 2.2˜2.8), U.S. Pat. No. 5,115,082 discloses a fluorine-containing poly(arylene ether) resin (dielectric constant: 2.4˜2.6), and U.S. Pat. No. 5,405,677 discloses a fluorine-containing aromatic resin (dielectric constant: 2.1˜2.5).
However, since a process of producing a printed circuit board is performed at a high temperature of 200˜450, a fluorine resin having a low glass transition temperature and having a low elastic modulus and a high linear expansion coefficient at high temperature has serious problems related to the insurance of the reliability of a printed circuit board.
Hence, attempts to develop materials having a low dielectric constant and a low dielectric loss index have been made. Typical examples of the materials include BCB (benzocyclobutene), SiLK (trade name of Dow Chemical Company) and the like.
However, these materials are also problematic in that they cannot be easily prepared, and in that they have low interface adhesion, thus deteriorating the mechanical properties of devices.
In particular, when SiLK, which is an organic material having a low dielectric constant, is used, a new process of accurately controlling the width and depth of trenches or via-holes is additionally required.